Swim Across the Atlantic ocean 3,462 miles

Out of idle lunchtime curiosity I was aimlessly surfing the web when I came across the Detroit Derby Girls site, I thought roller derby was dead and gone, but seems its coming back again.

Anyhow, I thought I'd see if they had merchandise which I could buy from my desk in Scotland. Though quite what for I can't imagine. The merch. is available from Detroit Threads (in Hamtramck, MI.)
(BTW If you're passing send me something suitable for a bloke who wears a small in tee shirts...)
But the threads' website isn't an online shop.

So, I thought I should find out how to get there from here, naturally, and I clicked the "map" link in the threads' web page.
That goes to maps.google and I chose to get directions from my office, this is what I got.

It starts weirldy enough in the lane out the back, and not in the street. Then in great and precise detail it sends me the length of the UK, and across from Dover to Boulougne and on to Le Havre on Atlantic coast of France.
Then it surpasses itself, at instruction 40, telling me to "Swim Across the Atlantic ocean 3,462 miles". Nice.

But what's perplexing me now is how they can tell that it'll take me "About 30 days"...

If you're still reading this rubbish you can see some nice photos of the Detroit Derby Girls in action here.